They finished just a few strokes behind Russian Larisa Ilchenko in the long-distance event, the first time it has featured in an Olympic Games.

Despite taking Britain's medals tally to 36, the pair, who led for most of the way, were upset at losing out on the gold and accused the winner of using dirty tactics and tugging on Patten's leg.

Soon after they plunged into Shinyi Lake in Beijing, where Britain has won numerous medals in the rowing regatta, Patten and Payne set the pace for the four-lap race.

The pair, who train together for four hours every day at Stockport Metro in Cheshire, had no lanes to separate them from other swimmers.

Behind the leaders, arms were clashing and racers were squeezed and pushed. Patten and Payne had to tolerate the constant tapping at their feet of Ilchenko and their other pursuers.

The tug on Patten's leg - which onlookers said could have earned the Russian a cautionary yellow card - was missed by judges on a boat alongside the swimmers.

After nearly two hours, world champion Ilchenko sprinted past the Britons in the final 100 metres to take the gold.

Afterwards Patten, who took bronze, said the 19-year-old Russian had deliberately pulled her leg back to gain an unfair advantage in the later stages.

"It's not good sportsmanship to pull on someone's feet. What's that all about?' said the 21-year-old student from Stockport. "Every part of your body is hurting. Your stomach is the size of a pea, because all the blood rushes to your arms, your body is saying stop but your head is saying 'come on keep going'. The last kilometre felt like 20, every time I looked up the finish seemed no closer."

Payne, 20, also from Stockport, who raced in the two individual medleys in the Water Cube last week, finished one and a half seconds behind Ilchenko, who completed the race in 1.59.27.7.

Payne said: "To get a medal is amazing. We didn't have a tactic, we just went out and swam. The course was really flat and one of the best I've ever swum. But I got weeds stuck in my costume and in my face.

"We didn't talk at all out there. We're best friends, we train together and we just kind of knew when to kick at the right time. Every part of my body was aching but I tried pushing for gold."